A135029 Numbers k such that k and k^2 both have digit sum 10. Multiples of 10 are omitted.

19, 46, 55, 145, 361, 451, 20251

Offset

1,1

Comments

A subsequence of A056020. - R. J. Mathar, Feb 10 2008

No further terms < 3*10^12 of the form 9*k+1, k=1,2,3,... - Lars Blomberg, Jun 28 2011

No further terms < 10^30. - Charles R Greathouse IV, Jun 29 2011

Links

Table of n, a(n) for n=1..7.

Example

Corresponding squares are 361, 2116, 3025, 21025, 130321, 203401, 410103001.

Prog

(PARI) dsum(n)=my(s=n%10); while(n\=10, s+=n%10); s
do(L)=my(E, F, G, H, t); for(a=1, L-1, for(b=0, a, for(c=0, b, for(d=0, c, for(e=0, d, E=10^a+10^b+10^c+10^d+10^e; for(f=0, e, F=E+10^f; for(g=0, f, G=F+10^g; for(h=0, g, H=G+10^h; for(i=0, h, t=H+10^i+1; if(dsum(t^2)==10, print1(t", ")))))))))));
do(30) \\ Charles R Greathouse IV, Jun 29 2011

Crossrefs

Cf. A056020.

Sequence in context: A378361 A115249 A325451 * A166148 A059657 A048970

Adjacent sequences: A135026 A135027 A135028 * A135030 A135031 A135032

Keyword

base,nonn

Author

Zak Seidov, Feb 10 2008

Status

approved